1. Field of the Invention
The present invention relates to an air and water supply apparatus for an endoscope which is designed so that air and water can be selectively sprayed from the distal end of the insert part of the endoscope.
2. Description of the Related Art
Endoscopes are generally designed to be capable of spraying water from a nozzle through a water tube to wash dirt off the surface of a viewing window provided at the distal end of the insert part. Since bacteria or viruses in the patient's body cavity are likely to invade the water remaining in the water tube, if the endoscope having been used for one patient is used for another with the remaining water left as it is, bacteria or viruses may be transmitted to the second patient. Accordingly, the remaining water must always be purged from the water tube after the endoscope has been used.
One typical example of conventional water purging systems has heretofore been arranged such that a switching valve is provided in a water tank for storing water to be supplied for washing and, with this switching valve switched to the position for purging, a water supply operation is conducted on the endoscope side to supply air into the water tube, thereby purging the remaining water from the water tube.
The above-described system suffers, however, from the following problems. The water tank is generally attached to a light source device or other associated device and therefore disposed away from the control part of the endoscope. Accordingly, the purging operation is commonly conducted when the endoscope is washed after being removed from the patient's body cavity since it is exceedingly difficult to carry out the purging operation with the endoscope being inserted in the patient's body cavity. However, as air for purging is supplied into the water tube, the water remaining in the water tube gushes out of the nozzle and scatters in the form of spray at the end of the purging operation. Therefore, if the water has been contaminated by bacteria or viruses, the purging operation may cause these bacteria or viruses to scatter in the room, which may invite in-hospital infection.
Thus for, substantially no attention has been paid to this phenomenon and therefore no measures have been taken to solve the problem. The present inventor, however, noticed the seriousness of this problem and came to invent the air and water supply apparatus for an endoscope of this application with a view to solving the problem.